Ichthyology Ichthyology - ECOL 482/582

• Dr. Peter Reinthal Office: BSE 120 ECOL 482/582 • Phone: 621-7518 • Email: [email protected] Fish Envy - Is It Wrong? • Office Hours: W-F 9:00-10:00 or by appointment • Teaching Assistant: Mary Jane Epps, [email protected] Office: W-F 3:00-4:00

• Lectures and Labs: Lecture 11:00 – 11:50 Wednesday and Friday (CBS 411) • Lab - 12:00 – 2:50 Wednesday and Friday (CBS 411)

• Web-site address: http://eebweb.arizona.edu - go to Courses, EEB course websites, Ecol482/582 or the URL is http://eebweb.arizona.edu/courses/ecol482_582/index.htm • • Books: Helfman, G., Collette, B., Facey, D. 1997. The Diversity of Fishes. Blackwell Science, Inc. – Or another Ichthyology Text – Bond 2nd ed. Or Moyle et al. can be used • • Suggested – This is a great book for fish aficionados - Paxton, J.R. and W.N. Eschmeyer (eds.) 1995. Encyclopedia of Fishes. Academic Press, N.Y.

• Lecture notes will be available as PDF files and there will be a series of handouts available as pdf files.

ECOL 482/582 ECOL 482/582 • The purpose of this course is to expose the participants to various topics in ichthyology. This includes laboratory, field and lecture work. The goals of the course are as follows: • • 1) To give the student a background and conceptual framework in phylogenetic systematics. • Great expectations: Given that an entire course (or lifetime) can be devoted to such intellectual pursuits, the professor strongly advocates that a phylogenetic framework is necessary to fully comprehend • Exams (60%) - You can take three exams and I the other goals of the class. will drop the lowest score of the three exams. If • 2) To expose the student to the diversity of fishes (BOTH living and fossil). A phylogenetic approach will be used to survey the diversity of fishes – starting with presumed primitive you miss an exam for any reason, you are lineages and fossil ancestors and working through the more advanced fishes. We will also look at major types of fishes found in Arizona and the Gulf of California. required to take other two and there will be no

• 3) To familiarize the student with the structure and function of fishes. This is important for three make up exams. All exams include lecture (20%) reasons: 1) you should be familiar with the basic structure of fishes, 2) many structures are important for identification purposes and 3) we will discuss the functional morphology of many and laboratory material (10%) and both the of these systems and how function/structure is used to in determining phylogenetic relationships. lecture and lab periods are scheduled for

• 4) To understand how fishes interact with their environments both ecologically and exams. physiologically.

• 5) To understand the challenges and tools available for the conservation and management of fishes both in Arizona and throughout the word.

1 ECOL 482/582 ECOL 482/582

• Great expectations: • Great expectations: • Paper or Project with Presentation (15%) - You • Lab (25%) - You must turn in a laboratory are also requested to do either a paper or laboratory project that is to be written up (10 notebook with all your lab work, identifications, page write up max - 10%) and present this to the field trips, dissections, notes, drawings, etc. class for 10 minutes (5%). Projects will address You are not permitted to copy other student’s the systematics, morphology, evolution and/or laboratory notebooks. If you miss a lab, see the ecology of fishes. You are permitted to work in teams and projects must be approved by Dr. TA or the Professor about getting access to the Reinthal. No duplicate projects are permitted lab to make up the missed work. and projects are approved on a first come first • Field Trips: Aravaipa and Mexico served basis.

Introduction What is a fish?

• What is a fish? • Distribution of water and fishes. • What about water? • Early fishes – overall context

2 What is a fish? Distribution - Where are the fish?

Of all vertebrate groups - fishes most plesiomorphic – Marine - Approximately 58% (about 13,630) of all Primitive phylogenetic position not equal unsuccessful - radiation of fish is unparalleled among vertebrates. species of bony fishes live in marine • Approximately 50,000 species of vertebrates, environments. approximately 25,988 species of fish in 483 families and 57 orders. • 4500 mammals, 9100 birds, 7082 reptiles, 4880 amphibians • ~85 jawless; ~850 cartilaginous and ~24,000 bony fish. • Why and how successful?

Distribution - Where are the fish? Where are the fish? Freshwater - approximately 42% If potential aquatic way of life (about 9,870) of fish open to vertebrate, highly species (Wootton, 1990) probable some fish has tried it somewhere at some time. BUT - Only about 0.01% • Found all over the globe: of earth's water is fresh. • Vertical distribution - ocean abyss to high altitude mountain streams (5200 m in hot springs in Tibet; 3812 m Lake Why? – So many species? Titicaca to 8000 meter deep – (cusk eels) - spans almost 13 km. In so little water?

3 Where are the fish? How many fish?

If potential aquatic ways of life open • Vast and diverse assemblage of to a vertebrate, highly probable organisms - consider variation in some group of fish has tried it life history traits; somewhere at some time. • 1. Fish populations vary in size • Temperature - Physiologically cope from 400 - 1000 individuals with hot soda lakes (43c) to sub-freezing waters of Antarctica (Cyprinodon diabolis - the devil's (-2 c). How do they survive?? Anti- hole pupfish – actually 125), to 10 freeze in blood. to the 15 (for some mesopelagic • Stunning range of morphologies stomiatids - Cyclothone spp. - no and adaptations: adaptation vs. other vertebrate populations phylogenetic constraint. approach this number).

How big are fish? How long do fish live?

• Consider variation in life history • Consider variation in traits; life history traits; • 2. Adult body size: • Small as 7.5 mm (tropical gobies, • 3. Life span ranges cyprinodonts, and cyprinids vie for from less than one title of smallest living vertebrate). year (annual fishes) • Largest fish is Whale shark to 150 years (halibut, (Rhincodon) - reaches lengths of up to 12m+, Ocean sunfish (Mola carp). mola) = weight of two tons, etc. tunas, swordfish, giant seabasses and catfish reach lengths of 10-12 feet and weigh half a ton.

4 How do fish breed? Are fish dimorphic?

• Consider variation in life • Consider variation in life history traits; history traits; • 4. Reproduction = open • 5. Secondary sexual dimorphism water spawning; • absent in herrings and spawning in nests, true anchovies; viviparity, ovoviviparity, • highly developed in or internal fertilization ceratioid Anglerfish followed by egg • Parental care ranges deposition. from non-existent to • Sex changes, parental highly developed. care etc.

How many fish in broods? Kinky sex in fish?

• Consider following • Consider variation in life variation in life history history traits; traits; • 7. Individuals may have • 6. Fecundity = # of eggs gonads of one sex only or shed in a single spawning of both sexes. varies Hermaphroditism may be • From one (Tomeurus sp.) protandrous, protogynous • Hundreds of thousands in or simultaneous. At least fish like cod (many eggs one species (Rivulus fail to be fertilized). marmoratus) capable of fertilizing own eggs.

5 Asexual fish? Metamorphosis in fishes? • Consider variation in life • Consider variation in life history traits; history traits; • 9. Some young miniature • 8. Asexual reproduction replicas of adults (e.g. occurs in Mollienesia formosa, viviparous surfperches), a hybrid species consisting • Others - young very solely of females, which mate different existence and are with males of either M. completely different in sphenops or M. latipinna. appearance (e.g. some Offspring = all female M. pelagic larvae of flatfishes). formosa.

Get the point yet? All sorts of way to look at diversity

• List could go on - but point is made (I think). • Use of the term "fish". • Fish vs. Fishes - clearly fish (in the taxonomic sense of Pisces) is not a real entity - because although it would include hypothetical ancestor • Fish do it all of fish (i.e. the first fish) and many of its descendents (some entirely fossil e.g. placoderms - acanthodians), it does not include • Diversity in and of itself interesting, yet somehow tetrapods - which are descendents of fish. we need to make sense of it. We need a context. • If early tetrapods did evolve from particular group of "fish" (evidently they did - either from rhipidistians or lungfish) - then tetrapods are, in • Theme of course will be understanding and fact, specialized fish...... concept of monophyly; • "Fish" as I have been using term NOT any monophyletic group - it exploring fish diversity within framework does not include ancestral fish and all descendents. provided by phylogenetic history. • Members certainly cannot be characterized by any unique feature(s) that don't also apply to vertebrates as a whole.

6 What is monophyly? What to do?

• Monophyletic Groups • So let’s accept “Fish” as a group • Paraphyletic Groups This course is going to concentrate on. • 1) Morphology and physiology • 2) Diversity of fish – Overall - phylogenetic context – Arizona and Gulf of California - identifications • 3) Ecology, behavior and conservation

Structural Patterns and Trends in What about the water? Diversification • Fish subsume (since Cope (1889) proposed) - Agnatha - jawless fishes and • High density, more viscous Gnathostome lines - hasn't really stood the test of time (explain later). • Low compressibility • Consider Agnathan briefly. • Earliest fish-like vertebrates with reasonable fossil record - middle Ordovician (440-510 mya) of North America, Europe and Australia. • Effective solvency – Universal solvent • Many early vertebrate groups tried hard external armor (dermal bone) – this is preserved. ~ 500 mya dermal bone with structural complexity evolved. • Low transparency • Evolution of calcified tissues has had profound effect on vertebrate evolution - and the origin of vertebrate skeletal structure - considerable interest • All oldest fish-like vertebrates sometimes called ostracoderms (shell-like skin). • All (at least partly) encased in some bony armor, lacked jaws, paired lateral fins. • Mouth was slit or oval opening towards front of animal. • From tail structure - adapted to bottom dwelling existence, feeding probably by suction?? using flexible floor of oralobranchial chamber and associated ventral branchial muscles as a pump.

7 Major Groups of Agnathans Major Groups of Agnathans

• 1. Osteostracida 2. Anaspida 1. Osteostracida 2. Anaspida 3. Pteraspidomorphida 3. Pteraspidomorphida • 1) Osteostracidan agnathans - 2) Anaspidan include thumb sized cephalaspids agnathans - streamlined (see Swedish ichthyologist Stensio) - characteristic anatomy bodies and small scales = head shield, pair of openings suggest strong swimmers. (presumably for the eyes) and Strange hypocercal tail single aperture for naso-hypohyseal canal. probably raised anterior end of • Stensios - external surface of body in swimming. brain = lampreys - suggested Immediately behind head is related. Are Lampreys living row of pores - thought to be gill osteostracidan that lost head shield - little support now openings.

Major Groups of Agnathans 2 living groups of agnathan fishes • 1. Osteostracida, 2. Anaspida, 3. Pteraspidomorphida • 3) Pteraspidomorphidan agnathans - Most successful in abundance, taxonomic diversity and duration in fossil • Hagfish and Lamprey = record – head, trunk enclosed in bony plates Traditionally together in cyclostomata • Not a good group BUT many uncertainties surrounding evolutionary interrelationships of various agnathan groups (both fossil and living) • Will go over in LIVE FISH SECTION

8 Jaws = GNATHOSTOMES GNATHOSTOMES

• Gnathostomes: the jawed fishes • Living Chondrichthyans - usually divided into • While agnatha cannot be called good Selachii or Elasmobranchi (sharks and rays) (monophyletic) group - there is very good and Holocephali (chimeroids). evidence for gnathostome monophyly. • Living Osteichthyans commonly regarded as • 4 major groups of jawed vertebrates: forming two major groups - • Living Chondrichthyes and Osteichthyes – Actinopterygii – Sarcopterygii (coelacanths, lungfish, Tetrapods). • Extinct Acanthodii and Placodermi.

FOSSIL GNATHOSTOMES FOSSIL GNATHOSTOMES

• Briefly - two fossil gnathostome radiations: • Briefly - two fossil gnathostome radiations: • 1) Acanthodians, or spiny-sharks = relatively conservative "fish-like" body form. Middle Silurian (440-408 mya) - disappear • 2) Placodermi - diversified and somewhat by middle Permian (290-245 mya). bizarre group of heavily armored • Acanthodians are teleostomes with small square crowned scales, stout spines before gnathostomes - flourished in Devonian (408-360 dorsal, anal and paired fins. Most acanthodians small fish, rarely exceeding mya) - almost restricted to this period. 20 cm - some reached over two meters. • Typically Placoderms are dorsoventrally • Large eyes, appear to be active mid-water swimmers. Show array of feeding compressed. All have head shield movably specialisations, some developing stout teeth, others were edentate with articulated with a trunk shield covering the modifications for filter feeding. anterior parts of body.

9 Gnathastome Summary SUMMARY

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